Computer micro-jobs

ABSTRACT

Computer micro-jobs are disclosed. A computer job is divided into micro-jobs. In one embodiment, the micro-jobs have a size that allows a particular micro-job to complete within an allotted time for which the particular micro-job owns a resource used to execute the micro-job. In one embodiment, the allotted time is a quantum. In one embodiment, an entire computer job is divided into micro-jobs and the computer job is then executed micro-job by micro-job until the entire computer job is complete. Each of the micro-jobs may complete its execution within its quantum, in one embodiment. In one embodiment, the execution of the micro-jobs is allocated to times when needed resources comply with one or more idleness criteria. A software program executed with micro-jobs may be run at all times while the computer is powered up without impacting the performance of other software programs running on the same computer system.

FIELD OF THE INVENTION

The present invention relates to executing software applications in acomputer environment. In particular, embodiments of the presentinvention relate to dividing a computer or input-output job of anapplication into micro-jobs and executing the micro-jobs.

BACKGROUND

In many multi-tasking operating systems, processes are broken up intoseveral threads. A thread is a piece of code executed by the operatingsystem (O/S). The concept of multi-threading is to allow several piecesof code (or threads) in one process to run “concurrently.” For example,if a word processor is running, the user can click on a “find menu item”to cause a pop-up box to appear. This pop-up can be moved andmanipulated independent of the main word processor window. Thus, thepop-up does not render the main word processor window inactive. This isan example of two different threads running within the word processorprocess.

The concept of multi-tasking is similar to multi-threading in that itgives the appearance of multiple pieces of code executing at the sametime on a single computer processor. A difference is that multi-taskingrefers to more than one process running on the computer andmulti-threading refers to more than one thread running within the sameprocess as with the example above.

The appearance of more than one process or thread running concurrentlyis a result of a multi-tasking scheduler scheduling threads to run invery small time increments, which may be referred to as “quanta.” Aquantum is a time slice given to a thread during which time that threadowns a CPU resource. The length of a quantum is in the range of about 20milliseconds to about 120 milliseconds on contemporary OperatingSystems. The exact times may vary depending on the hardware on which theO/S is running. Further, the O/S can change the value of the quantumgiven to a particular thread. For example, if a thread does not completeduring its first quantum, the O/S might increase or decrease the size ofthe quantum the next time the thread is scheduled to execute.

Due to the small length of a quantum compared to the human perception oftime and by executing threads in a round robin fashion, it appears thatthreads run concurrently. Contemporary multi-tasking O/S schedulers addpriorities to threads and various algorithms exist to optimally run thehigher priority threads before the lower priority threads. However, allthreads are presented to the O/S scheduler for immediate execution andthe O/S scheduler to the best of its ability gets all the threads tocomplete their execution as fast as it can based on their priority.

However, a problem with scheduling in this manner is that computerperformance is poorer than might be expected. Often, a process hesitatesor even freezes. For example, a process that renders on a display screenbased on user input is often unable to render as the user inputs databecause another process is consuming too much processor time.

The approaches described in this section are approaches that could bepursued, but not necessarily approaches that have been previouslyconceived or pursued. Therefore, unless otherwise indicated, it shouldnot be assumed that any of the approaches described in this sectionqualify as prior art merely by virtue of their inclusion in thissection.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 is a diagram of an architecture for executing micro-jobs, inaccordance with an embodiment of the present invention.

FIG. 2 is a diagram micro-scheduler that divides a computer job intomicro-jobs, in accordance with an embodiment of the present invention.

FIG. 3 is a flowchart illustrating steps of a process of dividing acomputer job into micro-jobs, in accordance with an embodiment of thepresent invention.

FIG. 4 is a block diagram that illustrates a computer system upon whichan embodiment of the invention may be implemented.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be apparent, however,that the present invention may be practiced without these specificdetails. In other instances, well-known structures and devices are shownin block diagram form in order to avoid unnecessarily obscuring thepresent invention.

Overview

The majority of computers do not utilize all of their resource capacity100% of the time. This is typically true even of computers thatseemingly are in high use twenty-four hours a day, seven days a week, aswell as computers that are only turned on for a portion of each day.Therefore, computer time and resources are wasted. For example, over atwenty-four hour period, a computer system that is used quite heavily,and which may have brief spikes in activity, may on average use onlyabout five to twenty percent of its resources.

A method, system, and apparatus are disclosed herein to utilize theseunused computer resources by dividing a computer job into micro-jobs. Amicro-job may be a very small sliver of computer code (e.g., arelatively small number of instructions). In one embodiment, the size ofa micro-job is such that it will finish execution within a time forwhich the micro-job was allocated a processing resource. For example,the number of operations in the micro-job is such that it will completeexecution within a quantum, in one embodiment. A micro-job may beshorter in length than a quantum.

In one embodiment, an entire computer job is divided into micro-jobs andthe computer job is then executed micro-job by micro-job until theentire computer job is complete. In contrast to attempting to run thecomputer job as quickly as possible given current resource constraintsor to scheduling the job to run “off-hours” to avoid significantlyimpacting other jobs and applications, the computer job may be run onthe computer on an ongoing basis, but in such minute pieces that it maybe imperceptible to the user or other computer jobs. Thus, the job maybe completely transparent to the user and to other jobs andapplications. The user does not need to schedule the job; with thismethod it can be run at any time, including during performance-criticaltimes.

In one embodiment, the micro-jobs are inserted for execution from timeto time based on selected criteria. In one embodiment, the execution ofthe micro-jobs is spread out over time based on determining some timeinterval to space the micro-jobs out by. The time interval does not needto be the same between each of the micro-jobs. In one embodiment, thecriterion for micro-job execution is based on resource availability. Forexample, in order to execute a micro-job, a determination is made as towhether one or more resources used by the micro-job comply with one ormore idleness criteria. If the idleness criteria are met, the micro-jobis executed.

Micro-Jobs

In one embodiment, the micro-jobs have a size that allows a particularmicro-job to complete within an allotted time for which the particularmicro-job owns a resource used to execute the processing job. In oneembodiment, each micro-job is such a size that it will complete withinits allotted time. However, it may be that some of the micro-jobs aretoo large to complete execution within their allotted time.

In one embodiment, the allotted time is a quantum. As previouslydiscussed, a quantum is a time slice given to a portion of computer code(e.g., a thread) during which time that code portion owns the CPUresource. As also previously discussed, different operating systems useddifferent quanta. Moreover, the quantum assigned to a particular codeportion may change based on circumstances during runtime. For example,an O/S might increase or decrease the size of the quantum allotted to athread. In one embodiment, the computer job is divided into micro-jobsbased on the size of the quantum that is expected to be allocated to thecomputer job. In another embodiment, the computer job is divided intomicro-jobs based on the size of the quantum that has been allocated tothe computer job. The determination as to what portions of the computerjob should be split off as micro-jobs may be made either prior toruntime or during runtime.

The micro-jobs are substantially smaller (for example, the smallest)work units that can be completed as a single unit while safely allowingfor a pause in execution until the next micro-job executes, inaccordance with one embodiment. By safely allowing for a pause inexecution, it is meant that the execution of a particular micro-job canbe delayed without affecting the outcome that results from execution ofthe all of the micro-jobs.

A micro-job may be a part of a thread. For example, a thread may bedivided into multiple micro-jobs. These micro-jobs may be scheduledsimilar to how a thread is scheduled. However, as previously stated, amicro-job will complete its execution if allowed to execute for aquantum or other time period for which it owns a processing resource, inone embodiment.

A micro-job may only need a very small amount of resources (e.g., CPUtime, memory allocation) at any one time. Such minimal use of resourcesat any one time may result in a stealthy process. Keeping the micro-jobssmall allows the computer job to use only a small amount of computerresources at one time. Thus, execution of a micro-job consumes asufficiently small amount of resources so as to not significantly impactperformance of other applications in the computer system, in accordancewith one embodiment of the present invention.

Dividing a Computer Job into Micro-Jobs I) Application Divides itsComputer Job into Micro-Jobs

An application program divides its computer jobs into a plurality ofmicro-jobs, in one embodiment. As used herein, the term plurality meansany number greater than one. FIG. 1 is a diagram of an architecture 100for executing micro-jobs, in accordance with an embodiment of thepresent invention. Each MJS-enabled application 115(1)-115(n) dividesits computer job (or jobs) into micro-jobs 125 to execute. For example,an application programmer can place calls at appropriate locations inthe application code that request permission from the MJS 110 to executea micro-job 125, which, in effect, divides the computer job intomicro-jobs 125. As examples, the computer job may perform maintenancesuch as backup, indexing, software updates, virus and malware scans, anddefragmentation. However, the MJS-enabled application 115(1)-115(n) mayalso be software other than maintenance.

Still referring to FIG. 1, the micro-job scheduler (MJS) 110 determineswhen micro-jobs 125 can be executed. Applications that are enabled towork with an MJS are referred to herein as MJS-enabled applications 115.In this embodiment, the MJS 110 has an application program interface(API) 130 to allow a particular MJS-enabled application 115 (e.g.,115(1)) to request that one or more micro-jobs 125 be allowed toexecute. The API 130 also allows an MJS-enabled application 115 tospecify by how much the micro-jobs 125 may be spread out, as will bediscussed more fully below. An example API is included herein below.However, the architecture 100 is not limited to the example API.

In one embodiment, the MJS 110 maintains a micro-job queue, such thatthe MJS 110 can determine which micro-job 125 should be allowed toexecute next. The execution of micro-jobs 125 is timed by the MJS 110 soas to have negligible impact on other applications.

The execution of the micro-jobs 125 can be specified by the MJS-enabledapplication 115 in an API call or other method of communication betweenthe application and the MJS. When the scheduler 105 determines that thenext micro-job 125 may execute without impacting other jobs, the MJS 110responds to the MJS-enabled application 115 by instructing theMJS-enabled application 115(1) to execute the micro-job 125.

In one embodiment, computer resource utilization is monitored andanalyzed to determine whether resource utilization complies with one ormore idleness criteria. The MJS causes micro-jobs 125 to be executedwhen the one or more idleness criteria are satisfied. Since, in oneembodiment, the time required for a particular micro-job 125 to executeis less than or equal to a quantum, any resources used by the micro-job125 are relinquished before the resources are needed by another job.Thus, resource utilization by the micro-job 125 may go unnoticed and themicro-job 125 may be invisible to its application's environment. In oneembodiment, the MJS schedules micro-jobs 125 based on time intervals.Time interval based scheduling is discussed below.

The MJS 110 also has a memory manager 140, in one embodiment. When theMJS 110 initializes, it is allocated memory by the operating system,some of which it uses for its own purposes and some of which itallocates to the MJS-enabled application 115. When an MJS-enabledapplication 115(1) launches, it requests a memory allocation from theMJS 110. The MJS 110 may determine how much memory to allocate to theMJS-enabled application 115(1) based on factors such as current computersystem memory utilization by all processes and the needs of theMJS-enabled application 115(1). Memory requirements may be specific toeach MJS-enabled application 115 and may be programmed into theMJS-enabled application 115 by a computer software programmer.

II) Scheduler Divides Computer Job into Micro-Jobs

In one embodiment, an MJS 110 divides a computer job into micro-jobs125. Referring to FIG. 2, the MJS 110 has micro-job division logic 210,which divides the computer job 205 into micro-jobs 125. The MJS 110 alsohave micro-job scheduling logic 220, which schedules the micro-jobs 125for execution. For example, the MJS 110 may work as a shell wrappedaround application programs that are not MJS-enabled. Thus, in thisexample, the shell MJS 110 is a complete software application throughwhich any executable can be run. Therefore, the shell MJS 110automatically divides the computer job from the executable intomicro-jobs 125, in one embodiment. In other words, the applicationprogrammer does not need to divide the application into micro-jobs 125,in this embodiment.

The shell MJS 110 divides the computer job from the executable intomicro-jobs 125 based on resource utilization, in one embodiment. Theshell MJS 110 may analyze the application and how the application runsto see what resources the application uses. For example, the shell MJS110 analyzes what resources the application uses and to what degree theapplication uses the resources. For example, when a disk defragmenterruns, the shell MJS 110 can determine what resources the applicationsuse (e.g., CPU, network, disk I/O). The shell MJS 110 automaticallydetermines how to divide the application into micro-jobs 125 based onthis analysis, in one embodiment. The shell MJS 110 may also determinehow to schedule the micro-jobs 125, based on this analysis.

The shell MJS 110 may use various parameters to determine how to dividethe computer job into micro-jobs 125 and/or determine how to schedulethe micro-jobs 125 for execution. These parameters may be based on userinput or established by the shell MJS 110. For example, the user mayspecify that a particular application have a high priority.

The shell MJS 110 schedules the micro-jobs 125 for execution based ontime intervals, in one embodiment.

In one embodiment, the MJS 110 is part of an operating system. In thisembodiment, the MJS 110 in the operating system may divide a computerjob into micro-jobs 125.

Scheduling Micro-Jobs Based on Time Intervals

In one embodiment, micro-jobs 125 are executed based on time intervals.For example, the MJS 110 schedules micro-jobs 125 based on timeintervals. For example, the MJS 110 spreads out execution of themicro-jobs 125 over time. For example, a computer job might take 12minutes to complete if not divided into micro-jobs 125. However, ifdivided into micro-jobs 125, the execution of the entire computer jobcan be spread out over 24 hours, with each particular micro-job 125executing once every few seconds.

As a particular example, if the quantum is 20 milliseconds the entirecomputer job might be completed in about 36,000 quanta. Thus, thecomputer job is divided into about 36,000 micro-jobs 125. The number ofmicro-jobs 125 might be slightly higher if some of the micro-jobs 125are smaller than a quantum. Given, a 20 ms quantum, over a 24-hourperiod there are 4,320,000 quanta. Therefore, the MJS 110 could executeone of micro-jobs 125 every 120 quanta or every 2.4 seconds. In thisparticular example, the micro-job enabled application would take 24hours to complete, but it may be undetectable even on extremely busysystems.

Scheduling Micro-Jobs Based on Events

In one embodiment, micro-jobs 125 are scheduled for execution based onevents. For example, the MJS 110 schedules micro-jobs 125 based on anumber of operations that occur. As another example, the MJS 110schedules micro-jobs 125 based on a number of quanta that occur. Thedifferent quanta may be of different sizes. Thus, the MJS 110 spreadsout execution of the micro-jobs 125 based on events, in one embodiment.

Resource-Based Scheduling of Micro-Jobs

In one embodiment, the micro-jobs 125 are scheduled based on resourceutilization. For example, the MJS 110 is a resource-based scheduler, inone embodiment. For example, the MJS 110 schedules micro-jobs 125 suchthat the micro-jobs 125 utilize only idle resources. The MJS 110determines whether resource utilization complies with one or moreidleness criteria to make scheduling decisions. As an example, the MJS110 may analyze disk activity. If an application other than theapplication with the micro-job 125 is using the disk, then the MJS 110waits until the other application is done to schedule the micro-job 125.The MJS 110 continues to monitor the disk I/O utilization, and allowsanother micro-job 125 to be scheduled if no other application is seekingaccess to disk I/O. However, if another application seeks utilization ofdisk I/O, then the MJS 110 will not allow another micro-job 125 to bescheduled, wherein the other application can utilize the disk I/O.

As another example, the MJS 110 may analyze network activity. If networktraffic is too high, the MJS 110 will not schedule any micro-jobs 125until traffic slows. If network traffic is low enough, then the MJS 110schedules a micro job for execution. The MJS 110 continues to check tomake sure that network traffic stays low enough. If network trafficstays low enough, another micro-job 125 may be scheduled. However, iftraffic gets too high, no further micro-jobs 125 are scheduled toexecute.

The MJS 110 may make resource-based scheduling decisions based on anytype of computer resource and any combination of resources. In oneembodiment, the MJS 110 has multiple queues of micro-jobs 125 awaitingpermission to execute. Each queue may correspond to a particularresource. For example, there may be a queue for micro-jobs 125 that needto utilize disk I/O, a queue for micro-jobs 125 that need to utilize anetwork, a queue for micro-jobs 125 that need to utilize a CPU, etc.There may also be one or more queues for micro-jobs 125 that utilize acombination of resources. The MJS 110 deploys micro-jobs 125 when theparticular resource or combination of resources is available. Aparticular micro-job 125 might require the use of two resources. Forexample, the particular micro-job 125 might require use of a networkresource and disk resource. However, the particular micro-job 125 doesnot need CPU resource. Even if the CPU resource utilization is currentlyhigh, the particular micro-job 125 can still be scheduled and executed.

The MJS-enabled application 115 sends parameters to the MJS 110 tocontrol resource utilization, in accordance with an embodiment of thepresent invention. Control of resource utilization includes, but is notlimited to, disk I/O, CPU and network. For example, the MJS-enabledapplication 115 can request a micro-job 125 be executed pending anycombination of threshold levels of the above three resources. Moreover,the MJS-enabled application 115 can specify different resource thresholdlevels for different micro-jobs 125. For example, the MJS-enabledapplication 115 specifies a different resource threshold level with eachmicro-job 125, in accordance with one embodiment. Therefore,fine-grained resource management is possible. When the MJS 110calculates resource utilization, it is the resource utilization ofprocesses other than the MJS-enabled application 115 that is measured,in accordance with one embodiment of the present invention. Thefollowing example in which the CPU utilization threshold is set to 20percent is used to illustrate. If CPU utilization is below 20 percentprior to allowing the MJS-enabled application 115 to execute, CPUutilization may increase to over 20 percent when the micro-job(s)execute. This increase beyond 20 percent is not considered a CPUresource utilization violation, in this example. Similar principlesapply to network and disk I/O resources.

If the MJS 110 executes outside of the operating system, the MJS 110self-limits in its own resource utilization, in one embodiment. Forexample, the MJS 110 monitors its own resource utilization and if itsown resource utilization gets too high, the MJS 110 makes a request tothe operating system to stop scheduling the MJS 110 for a period oftime.

Process Flow

FIG. 3 is a flowchart illustrating steps of a process 300 for executinga computer job by dividing the computer job into micro-jobs 125, inaccordance with an embodiment of the present invention. In step 302, thecomputer job is initiated. The computer job may be from an MJS-enabledapplication 115. However, the computer job does not have to beassociated with an MJS-enabled application 115.

As an example, in step 302, an MJS-enabled application 115 program islaunched when the computer system is booted, in one embodiment. If theMJS-enabled application 115 does not have a computer job to perform, theMJS-enabled application 115 sits in an idle state until it has acomputer job to run. In this idle state, the MJS-enabled application 115may perform some functions such as occasional monitoring. At some point,the MJS-enabled application 115 has a computer job to perform, such asdefragmenting a storage medium, or scanning for viruses. The computerjob could be to defragment a single disk and the files stored on it,wherein the MJS-enabled application 115 defragments that disk on anongoing basis.

A small amount of memory may be allocated to the MJS-enabled application115 when it is launched. The amount that is allocated can be very smallbecause the MJS-enabled application 115 typically only attempts toexecute a single micro-job 125 at one time. However, in some cases, theMJS-enabled application 115 might attempt to execute multiple micro-jobs125 without waiting for other processes to execute. For example, if theMJS 110 determines that the required computer system resources are idle,the MJS 110 may allow the MJS-enabled application 115 to executemultiple micro-jobs 125 in a row without another process utilizing theresources that are utilized by the micro-jobs 125.

In step 304, the computer job is divided into micro-jobs 125. The sizeof a particular micro-job 125 allows the particular micro-job 125 tocomplete within an allotted time for which the particular micro-job 125owns a resource used to execute the processing job, in one embodiment.The micro-jobs 125 may be of a size such that execution of themicro-jobs 125 utilizes a sufficiently small amount of resources so asto not significantly impact performance of other jobs in the computersystem. In one embodiment, dividing the computer job into micro-jobs 125comprises selecting the size of the micro-jobs 125 such that each microjob 125 is able to complete execution within an allotted time for whichthe computer job is given ownership of a resource used to execute themicro job 125.

In one embodiment, the computer job is divided into micro-jobs 125 by anapplication that owns the computer job. Dividing the computer job intomicro-jobs 125 may be accomplished by instructions within an MJS-enabledapplication 115. In general, these instructions are decision points inthe MJS-enabled application 115. For example, the instructions can beAPI calls to the MJS 110 that request permission to execute a micro-job125. However, the MJS 110 can be integrated with the MJS-enabledapplication 115, in which case the instructions could be calls to ascheduling function within the MJS-enabled application 115. Othertechniques might be used to divide the computer job into micro-jobs 125.For example, in one embodiment, the computer job is divided intomicro-jobs 125 by micro-job division logic in a shell MJS 110.

Step 306 is execution of the micro-jobs 125. In one embodiment, theentire computer job is divided into micro-jobs 125 and the computer jobis then executed micro-job 125 by micro-job 125 until the entirecomputer job is complete. For example, an entire defragmentation job isdivided into micro-jobs 125, which are executed one at a time until theentire defragmentation job is complete. A particular micro job 125completes its execution in less than or equal to the allotted time, inone embodiment.

Executing micro-job 125 by micro-job 125 is not limited to sequentialone-by-one execution, although it includes sequential one-by-oneexecution. Multiple micro-jobs 125 could be executed at the same time.For example, if there are multiple CPUs, different micro-jobs 125 couldexecute on different CPUs at the same time.

In one embodiment, the scheduling of the micro-jobs 125 is based onresource utilization. In this embodiment, a determination is made, foreach of the micro-jobs 125, as to whether utilization of one or moreresources of the computer system to be used by the particular micro-job125 satisfies one or more idleness criteria. The idleness criteria for aparticular resource may be based on one or more factors. For example,CPU utilization is used as an idleness criterion for CPU resourceutilization, in one embodiment. Thus, the micro-jobs 125 are onlyexecuted at times when the resources of the computer system needed bythe micro-jobs 125 are sufficiently idle. The idleness criteria arebased on resource thresholds, in one embodiment. For example, resourcethresholds may be used, wherein a micro-job 125 of an MJS-enabledapplication 115 only executes if resource utilization by other processesis below a threshold specified by the MJS-enabled application 115. Theexample API described below contains one example of some resourcethreshold parameters. However, process 300 is not limited to theseresource threshold parameters.

In one embodiment, the scheduling of the micro-jobs 125 is based on timeintervals. In one embodiment, the execution of the computer job isspread over a period of time. For example, the computer job might bespread out over several hours. Based on how many micro-jobs 125 intowhich the computer job is divided, a determination can be made as to howto spread the micro-jobs 125 out over time. The time between successivemicro-jobs 125 does not need to be uniform.

In one embodiment, an application program that initiated the computerjob runs on an on-going basis, continuing to run as long as the computersystem remains booted, but remains idle while no work needs to beperformed. For example, a disk defragmenter to virus detectionapplication program continues to run. Thus, even if the computer jobcompletes, the application program continues to run in idle mode waitingfor the next segment of work. Thus, the application program does notneed to be re-launched when it has another computer job to perform. As aresult, the application program does not consume additional resourcesthat are typical of launching an application program. When theapplication program determines that it has another computer job to do,the computer job is divided into micro-jobs 125, and the micro-jobs 125are executed over time. For example, a disk defragmenter applicationprogram may determine that additional storage medium defragmentationshould be done based on changes to the computer's storage medium.

EXAMPLE API

An embodiment of the present invention is an API for allowing anMJS-enabled application 115 to interface with an MJS 110. The exampleAPI has the following resource threshold parameters for CPU, disk, andnetwork.

CPU Utilization threshold

Pending Disk I/O Count threshold

Network Utilization threshold

The above parameters can be specified for each micro-job 125. In otherwords, different micro-jobs 125 can be assigned different resourcethreshold parameters. For example, for a micro-job 125 that uses thenetwork, a network threshold may be used. However, the network thresholdcould be zero for micro-jobs 125 that do not use the network. Thus,fine-grained resource management is provided for, in accordance with anembodiment of the present invention.

As a particular example, the MJS-enabled application 115 can requestthat a particular micro-job 125 be executed only if the CPU utilizationis below 50%, and the I/O Disk Utilization is below 40%, and networktraffic is below 60%. Any combination of the resource threshold factorscan be used, including none at all. The CPU utilization thresholddifferentiates between MJS's use of the CPU as opposed to that of anyother job, in accordance with an embodiment of the present invention.

The following two parameters are used to specify how frequently resourceutilization should be measured.

CPU Utilization Window

Network Utilization Window

The CPU Utilization Window parameter defines a time window over whichCPU utilization is calculated. For example, CPU utilization over thelast n milliseconds is averaged. The network utilization window definesa time window over which network utilization is calculated. Theseparameters may be internal to the MJS 110. However, an MJS-enabledapplication 115 may override these parameters. The pending disk I/O isabsolute at any point in time and thus it does not have to becalculated.

A mandatory idle time parameter may be passed from the MJS-enabledapplication 115 to the MJS to control how the micro-jobs 125 are spreadout over time. The mandatory idle time parameter is optional.Furthermore, when used, the mandatory idle parameter may have a value ofzero.

Mandatory Idle Time

The MJS 110 keeps track of “idle time,” which is defined as system idletime after all micro-jobs 125 have executed. As previously mentioned,MJS-enabled application 115(s) can queue up micro-jobs 125 with the MJS110. When there are no micro-jobs 125 on the MJS queue, the MJS 110waits for the specified Mandatory Idle Time and then wakes up andauthorizes the MJS-enabled application 115(s) to perform additionalwork. For example, an MJS-enabled defragmenter might first execute anumber of micro-jobs 125 to defragment a disk drive, and then be pausedby the MJS 110. After the specified Mandatory Idle Time, the MJS 110calls the MJS-enabled defragmenter to authorize additional work. Forexample, the MJS-enabled defragmenter might execute a clean-up job, suchas releasing memory. Mandatory Idle Time can be a default parameter thatcan be adjusted by an MJS-enabled application 115.

The following parameters relate to waiting to execute a micro-job 125when resource utilization is above a threshold.

Wait Time

Maximum Wait Time

If the MJS 110 determines that resource utilization is currently toohigh to execute a micro-job, the MJS 110 waits for the specified WaitTime and then re-checks resource utilization. The Wait Time parametercan be increased each time the MJS 110 determines that resourceutilization is too high. For example, the MJS 110 can increase the WaitTime parameter until the Max Wait Time is reached. These parameters canbe specified by the MJS-enabled application 115 when it is firststarted. An MJS-enabled application 115 can adjust these parametersduring its run time.

Hardware Overview

FIG. 4 is a block diagram that illustrates a computer system 400 uponwhich an embodiment of the invention may be implemented. Steps ofprocess 300 are stored as instructions one or more of thecomputer-readable media of system 400 and executed on the processor ofcomputer system 400. Computer system 400 includes a bus 402 or othercommunication mechanism for communicating information, and a processor404 coupled with bus 402 for processing information. Computer system 400also includes a main memory 406, such as a random access memory (RAM) orother dynamic storage device, coupled to bus 402 for storing informationand instructions to be executed by processor 404. Main memory 406 alsomay be used for storing temporary variables or other intermediateinformation during execution of instructions to be executed by processor404. Computer system 400 further includes a read only memory (ROM) 408or other static storage device coupled to bus 402 for storing staticinformation and instructions for processor 404. A storage device 410,such as a magnetic disk or optical disk, is provided and coupled to bus402 for storing information and instructions. The computer system 400can have any number of processors 404. For example, computer system 400is a multi-processor system, in one embodiment. The processor 404 canhave any number of cores. In one embodiment, the processor 404 is amulti-core processor 404. Computer system 400 can be used in ahyper-threaded machine.

Computer system 400 may be coupled via bus 402 to a display 412, such asa cathode ray tube (CRT), for displaying information to a computer user.An input device 414, including alphanumeric and other keys, is coupledto bus 402 for communicating information and command selections toprocessor 404. Another type of user input device is cursor control 416,such as a mouse, a trackball, or cursor direction keys for communicatingdirection information and command selections to processor 404 and forcontrolling cursor movement on display 412. This input device typicallyhas two degrees of freedom in two axes, a first axis (e.g., x) and asecond axis (e.g., y), that allows the device to specify positions in aplane.

The invention is related to the use of computer system 400 forimplementing the techniques described herein. According to oneembodiment of the invention, those techniques are performed by computersystem 400 in response to processor 404 executing one or more sequencesof one or more instructions contained in main memory 406. Suchinstructions may be read into main memory 406 from anothermachine-readable medium, such as storage device 410. Execution of thesequences of instructions contained in main memory 406 causes processor404 to perform the process steps described herein. In alternativeembodiments, hard-wired circuitry may be used in place of or incombination with software instructions to implement the invention. Thus,embodiments of the invention are not limited to any specific combinationof hardware circuitry and software.

The term “machine-readable medium” as used herein refers to any mediumthat participates in providing data that causes a machine to operate ina specific fashion. In an embodiment implemented using computer system400, various machine-readable media are involved, for example, inproviding instructions to processor 404 for execution. Such a medium maytake many forms, including but not limited to, non-volatile media,volatile media, and transmission media. Non-volatile media includes, forexample, optical or magnetic disks, such as storage device 410. Volatilemedia includes dynamic memory, such as main memory 406. Transmissionmedia includes coaxial cables, copper wire and fiber optics, includingthe wires that comprise bus 402. Transmission media can also take theform of acoustic or light waves, such as those generated duringradio-wave and infrared data communications. All such media must betangible to enable the instructions carried by the media to be detectedby a physical mechanism that reads the instructions into a machine.

Common forms of machine-readable media include, for example, a floppydisk, a flexible disk, hard disk, magnetic tape, or any other magneticmedium, a CD-ROM, any other optical medium, punchcards, papertape, anyother physical medium with patterns of holes, a RAM, a PROM, an EPROM, aFLASH-EPROM, any other memory chip or cartridge, a carrier wave asdescribed hereinafter, or any other medium from which a computer canread.

Various forms of machine-readable media may be involved in carrying oneor more sequences of one or more instructions to processor 404 forexecution. For example, the instructions may initially be carried on amagnetic disk of a remote computer. The remote computer can load theinstructions into its dynamic memory and send the instructions over atelephone line using a modem. A modem local to computer system 400 canreceive the data on the telephone line and use an infrared transmitterto convert the data to an infrared signal. An infrared detector canreceive the data carried in the infrared signal and appropriatecircuitry can place the data on bus 402. Bus 402 carries the data tomain memory 406, from which processor 404 retrieves and executes theinstructions. The instructions received by main memory 406 mayoptionally be stored on storage device 410 either before or afterexecution by processor 404.

Computer system 400 also includes a communication interface 418 coupledto bus 402. Communication interface 418 provides a two-way datacommunication coupling to a network link 420 that is connected to alocal network 422. For example, communication interface 418 may be anintegrated services digital network (ISDN) card or a modem to provide adata communication connection to a corresponding type of telephone line.As another example, communication interface 418 may be a local areanetwork (LAN) card to provide a data communication connection to acompatible LAN. Wireless links may also be implemented. In any suchimplementation, communication interface 418 sends and receiveselectrical, electromagnetic or optical signals that carry digital datastreams representing various types of information.

Network link 420 typically provides data communication through one ormore networks to other data devices. For example, network link 420 mayprovide a connection through local network 422 to a host computer 424 orto data equipment operated by an Internet Service Provider (ISP) 426.ISP 426 in turn provides data communication services through the worldwide packet data communication network now commonly referred to as the“Internet” 428. Local network 422 and Internet 428 both use electrical,electromagnetic or optical signals that carry digital data streams. Thesignals through the various networks and the signals on network link 420and through communication interface 418, which carry the digital data toand from computer system 400, are exemplary forms of carrier wavestransporting the information.

Computer system 400 can send messages and receive data, includingprogram code, through the network(s), network link 420 and communicationinterface 418. In the Internet example, a server 430 might transmit arequested code for an application program through Internet 428, ISP 426,local network 422 and communication interface 418.

The received code may be executed by processor 404 as it is received,and/or stored in storage device 410, or other non-volatile storage forlater execution. In this manner, computer system 400 may obtainapplication code in the form of a carrier wave.

In the foregoing specification, embodiments of the invention have beendescribed with reference to numerous specific details that may vary fromimplementation to implementation. Thus, the sole and exclusive indicatorof what is the invention, and is intended by the applicants to be theinvention, is the set of claims that issue from this application, in thespecific form in which such claims issue, including any subsequentcorrection. Any definitions expressly set forth herein for termscontained in such claims shall govern the meaning of such terms as usedin the claims. Hence, no limitation, element, property, feature,advantage or attribute that is not expressly recited in a claim shouldlimit the scope of such claim in any way. The specification and drawingsare, accordingly, to be regarded in an illustrative rather than arestrictive sense.

1. A machine-implemented method comprising the steps: dividing acomputer job into a plurality of micro-jobs, wherein dividing thecomputer job comprises selecting the size of the micro-jobs based on anallotted time for which the computer job is given ownership of aresource; and executing the computer job by causing the plurality ofmicro-jobs to use the resource to execute.
 2. The method of claim 1,wherein selecting the size of the micro-jobs comprises selecting thesize of the micro-jobs such that each micro job is able to completeexecution within an allotted time for which the computer job is givenownership of a resource used to execute the micro job.
 3. The method ofclaim 2, wherein the computer job is completed by completing executionof each of the individual micro jobs in less than or equal to theallotted time.
 4. The method of claim 1, wherein executing the computerjob comprises: determining when one or more resources required to run aparticular micro-job comply with one or more idleness criteria; and inresponse to a determination that utilization of the one or moreresources required to run the particular micro-job complies with one ormore idleness criteria, causing the particular micro-job to execute tocompletion within the allotted time.
 5. The method of claim 1, whereinexecuting the computer job comprises: determining a length of time towait between execution of successive micro-jobs.
 6. The method of claim5, wherein determining the length of time is based on the number ofmicro-jobs into which the computed job is divided and a period of timeover which the computer job is to be spread out over.
 7. The method ofclaim 1, wherein executing the computer job comprises: waiting a timeinterval between execution of successive micro-jobs.
 8. The method ofclaim 1, wherein executing the computer job comprises: waiting a numberof operations to between execution of successive micro-jobs.
 9. Themethod of claim 1, wherein executing the computer job comprises: waitinga number of quanta to between execution of successive micro-jobs. 10.The method of claim 1, wherein at least two of the quanta are of adifferent size from each other.
 11. The method of claim 1, wherein atleast one of the micro-jobs comprises a portion of a thread.
 12. Themethod of claim 1, wherein the allotted time is a quantum.
 13. Amachine-implemented method comprising the steps: splitting off amicro-job from a computer job that is to execute under control of anoperating system that allocates an amount of time for which codeportions are given ownership of a resource, wherein the size of themicro job is selected such that the micro job is expected to completeexecution within the allotted time; and causing the micro-job to executeto completion within the allotted time, wherein the micro-jobrelinquishes ownership of the resource no later than the end of theallotted time.
 14. The method of claim 13, further comprising: splittingoff a plurality of micro-jobs from the computer job, wherein the size ofeach of the micro jobs is selected such that each micro job is expectedto complete execution within the allotted time; and causing eachmicro-job to execute to completion within the allotted time for therespective micro job, wherein each micro-job relinquishes ownership ofthe resource no later than the end of the allotted time for therespective micro job.
 15. The method of claim 13, wherein causing eachmicro-job to execute causes the computer job to complete.
 16. The methodof claim 13, wherein causing the micro-job to execute to completioncomprises: determining when one or more resources required to run themicro-job comply with one or more idleness criteria; and in response toa determination that utilization of the one or more resources requiredto run the micro-job complies with one or more idleness criteria,causing the micro-job to execute to completion within the allotted time.17. The method of claim 13, wherein the step of splitting off amicro-job comprises: determining a number of operations of the computerjob that can be executed, using the resource, within the allotted time;and spitting off less than or equal the number of operations from thecomputer job to form the micro-job.
 18. The method of claim 13, whereinthe micro-job comprises a portion of a thread.
 19. The method of claim13, wherein the allotted time is a quantum.
 20. A machine-implementedmethod comprising the steps of: dividing, into a plurality ofmicro-jobs, a computer job that is to execute under control of anoperating system that allocates an amount of time for which codeportions are given ownership of a resource, wherein dividing thecomputer job comprises selecting the size of the micro-jobs based on anamount of time for which the computer job is given ownership of aresource; and spreading execution of the computer job over a period oftime.
 21. The method of claim 20, wherein the step of spreadingexecution of the computer job comprises determining a length of time towait between execution of two successive micro-jobs of the computer job.22. The method of claim 21, wherein determining a length of time isbased on a number of micro-jobs into which the computer job is dividedand the time period over which the computer job is to be spread outover.
 23. The method of claim 20, wherein the step of spreadingexecution of the computer job over a period of time comprises:determining when one or more resources required to run a particularmicro-job comply with one or more idleness criteria; and in response toa determination that utilization of the one or more resources requiredto run the particular micro-job complies with one or more idlenesscriteria, causing the particular micro-job to execute to completionwithin the allotted time.
 24. The method of claim 21, wherein the stepof spreading execution of the computer job comprises waiting a lengthbetween execution of two successive micro-jobs of the computer job. 25.The method of claim 21, wherein the step of spreading execution of thecomputer job comprises waiting a number of operations between executionof two successive micro-jobs of the computer job.
 26. The method ofclaim 21, wherein the step of spreading execution of the computer jobcomprises waiting a number of quanta between execution of two successivemicro jobs of the computer job.
 27. The method of claim 21, wherein atleast two of the quanta are of a different size from each other.
 28. Themethod of claim 21, wherein at least one of the micro-jobs comprises aportion of a thread.
 29. The method of claim 21, wherein the allottedtime is a quantum.